Dr Erin Dunn, a psychiatrist at Massachusetts General Hospital, examined lost milk teeth from six-year-olds and found those with thinner enamel were more likely to have attention deficit issues.
They asked the parents of 37 children aged six and up in California to donate their teeth when they fell out.
After analyzing each tooth with high-resolution imaging, they compared their analyses behavioural assessments of the children.
They found differences in dimensions and qualities of their teeth were better predictors of mental health than factors that psychiatrists would normally look for, such as the neighbourhood they live in or their family setup.
This is interesting but I would have liked to see a study of adult teeth.